Composite parts, such as those used in the manufacture of aircraft, can be constructed using various production methods, such as filament winding, tape placement, overbraid, chop fiber roving, coating, hand lay-up, or other composite processing techniques and curing processes. Most of these processes use a rigid cure tool/mandrel on which composite material is applied and then cured into a rigid composite part. For example, automated fiber placement (AFP) machines may be used to place fiber reinforcements on molds or mandrels to form composite layups. Following, composite parts may be cured within an autoclave that applies heat and pressure to the part during a cure cycle.
Some composite part geometries include internal cavities that may require a tool such as a supporting bladder that is placed in the cavity to ensure that the part geometry is properly maintained during application of composite material or when processed under autoclave pressure. The supporting bladder may be an inflatable bladder that can easily fit into an internal cavity prior to cure and then be inflated during an autoclave cure process so as to react to the autoclave pressure force applied to the part. Typically, such inflatable bladders are pressurized by venting them to the autoclave pressure through a vacuum bag.
However, the bladders that are used to support a composite part (e.g., a stringer or other longitudinal structural piece in a framework) for autoclave curing may not suitable when alternatively curing the part out-of-autoclave (e.g., as performed with repairs). In this case, the part and the bladder are exposed to different temperature and pressure conditions than in an autoclave such that an inflatable bladder may not perform properly and could in fact negatively impact final part characteristics. This creates a need for a support tool that can fit into a composite part cavity prior to cure, can conform to the internal geometry of the part cavity during out-of-autoclave curing, and finally can reduce in size to be removed from the part after cure.